Method of and apparatus for the direct synthesis of ammonia at very high pressures



al". 13, i923.. L44887 G. CLAUDE METHOD OE AND APPARATUS FOR THE DIRECTSYNTHESIS OE AMMONIA AT VERY HIGH PREssUREs Filed Nov. '7, 19.18

Patented Mar. 13, 1923.

GEORGESV CIf-AUDE, or rARIs, FRANCE,

ANCNYME POUR LETUDE ET LExPLoITATIoN CLAUDE'. CE PARIS, FRANCE.

AsSIGNoR 'ro LAIRLIaUInE, SOCIETE DES IRoCED'ES ,eEoRGEs METHOD or ANDAPPARATUS ECR THE DIRECT SYNTHESIS oE'AI/IMONIA AT VERY HIGH PRESSURES.

Application filed November 7, 14.918.` Serial No. 261,578.

To all whom t may concern Beit known-that I, GEORGES CLAUDE, a citizenof the Republic of France, residing at Paris, France, have inventedcertain new 5 and useful Improvements in Methods of and Apparatus forthe Direct Synthesis of Ammonia at Very High Pressures; and I do herebydeclare the following to be av full, clear, and exact description of theinvention,

such as will enable others skilled in the art to which it appertains tomake and use the same.

In anearlier application #222,502, dated Manch 14:, 1918, I havedescribed a method 15 for the synthetic manufacture of ammonia,consisting in passing a mixturev of nitrogen and hydrogen compresse-d toa very high pressure, called hyperpressuref Vin the neighborhood of 400to 2,000 atmospheres,

over a catalyzing material at a temperature in the neighborhood of 500vto 7000 C. vThe ammonia formed is separated by liquefaction at ordinarytemperature, the residual gas being treated in a second catalyzing ap`paratus, then in a third and in a fourth, if

necessary, with liquefaction of the ammonia formed at the prevailingtempera-ture, between each passage through the catalyzing apparatus.After the last catalysis, the gaseous residue, if it still containshydrogen, may be employed in the production of power.

T he method and apparatus forming the subject matter of the presentinvention permits of employing a singlei catalytic apparatus instead ofa number. With this object, I utilize a peculiarity resulting from theemployment of hyperpressures, and involving the ivery great differenceof density between the gas which has reacted and contains ammonia, andthat composed of nitrogen and hydrogen which is about to react.

- At corresponding temperatures, the first has a density much greaterthan the second, be-

cause of the contraction of the gaseous mixture N24-SH2 during its'conversion into 2NII3. The difference ofv density is lmade very great bythe high proportion of ammonia resulting from the use ofhyperpresbination by the very Strongly active pressure and by theparticularly high compresfOrmed. Y

In the accompanyingl drawing, Figs. 1v Aand 2 represent, respectively,two forms of sures, which provides a high factor of coin-l sibility ofammonia as vcompared to'that of its constituents.

It follows that I am thus able to obtain Without intermediate mechanisma very active circulation of the gas at the same pressure, even in thetwo compartments supposed under the same pressure of an exchanger oftemperature. I am able, therefore, as heref inafter shown to cause bythis means a circulation of a part of the gas, which has passed througha portion of the catalyzing material, thereby bringing it to ordinarytemperature and condensing the ammonia which it contains; thev remaininggas, which has not reacted, returning to the catalyzing apparatus and tothe temperature necessary for combination, and mixing with the gas whichhas not been separated from its ammonia content. -This diminishes ofcourse, the concentration of ammonia in the gas and adds to theefficiency of the synthesis. ll pass this. gaseous mixture throughanother portion of the catalyzing material, then treat a part` asbefore, to again extract ammonia. It will be understood that byrepeating this operation a certain number of times, it is possible tofinally extract by successive fractions, all of the ammonia apparatuscapable of use in carrying out the invention.

In Fig. 1 T1 is a horizontal shell of steel to support hyperpressures,preferably tubular in form; T2 is a thin metallic shell pre` serving theshell T,l from the destructive action of the temperature and the gas asa result of interposition between T1 and T2 of a bed of insulatingmaterial. A shell T3 within T2 is supported at one end by an annularplug M and provides between these two shells an annular chamber traveledby the gas about to react, which enters the apparatus through-K and isdirected in this space towards vA. Thereafter it travels throughtheshell T3 and the part of the shell T which extends beyond the shell T3,both being filled with catalyzing material.

In its travel through K and A, the .gas about to react, being in contactwith the tube'TS, is heated to the reaction temperature, that is to say,500 to ()o C, as a result of heat liberated by the reaction when theapparatus is functioning normally, or by contact with electric heatingmeans S in starting .the reaction. The gas, passing thence through thecatalyzing material in T., and colnbination being eiicctedprogressively, arrives at the end of T3. It ought to have a temperaturesuflicient to continue the synthesis in the part of the shell T2 beyondM which does not itself constitute, as the preceding part does, anexchanger otl temperature with the shell T3.

The proportion of ammonia content in the gas leaving T3 is veryimportant and it is necessary in order to continue the reaction toeliminate all or a part ot the ammonia formed. For this purpose, avertical tubc t communicates with 'l2 through lateral plug K1, and witha collecting receptacle C, the exterior walls of which may be cooled byWater. A concentric tube t, ot' a smaller diameter )asses from theinterior ot' the receptacle and communicates with the axis of thecatalyzing shell T2. The gas charged with ammonia descends by t, intothe receptacle C; the ammonia which it contains condenses and iswithdrawn through the valve r. The gas becomes thusI less dense andreturns to the catalyzinfr shell tube T2 through the outer tube t.

Together these tubes t and t1 provide au exchanger of temperature whichshould be insulated, so that the gas returning through t may be at atemperature very near that of the gas passing in T2 thereby preventing.

the lowering of the ten'lperature below that necessary for the reaction.

A second separation of gas is effected a. little Jfurther on in thecatalyzer T2 by a second device K2 similar to that just described andthe separation is repeated as many times as is necessary for thecombination of thc gas to be practically complete in the shell T2. Theresidual gas containing the impurities of the initial gas leaves by atube (not shown) placed at the extreme right of the apparatus.

Fig. 2 represents another apparatus in which the gas about to react isheated by indirect contact with all of the catalyZ-ing material. It isapplied to the particular case where the gas passes, not around thecatalyzing shell, but through .the interior thereof by a central tube u.During its passage in the tube, it is heated to the tempera-ture of thereaction. The withdrawal of the ammonia is then accomplished byapparatus analogous to that above described such as K and the residualgas is withdrawn to the exterior by a tube placed at the extreme rightof T1. In either apparatus, the heat liberated by the reaction, which ismore than suilicient for heating the incoming gases to the necessarytemperature, is eliminated at the exterior of tube T,L by means of asuitable cooling medium.

1 claim:

l. A method for the direct synthesis of ammonia at very high pressureswhich comprises, heating a compressed gaseous mixture of nitrogen andhydrogen by the heat of the combination of these gases to thetemperaturcI or' the reaction, passing it through a portion ot a body ofcatalyzing material, circulating it by difference of density so that apart ofthe mixture after reacting descends into a cooler region. thuslowering the temperature or' the mixture to the neighborhood ofatmospheric temperature, separating the ammonia thus liqueiethreheatingby indirect contact with the descending gas the gas ascending andseparated from the ammonia. sending it then with a part of the mixturewhich has not participated in the circulation through another porton ot'the catalyzing material where the reaction continues. causing successiveseparations ot' ammonia as before and rejecting the residual gas.

2. A method for the direct synthesis ot' ammonia at very high pressureswhich comprises, passing a compressed gaseous mixture of nitrogen andhydrogen in heat exchange relation with a body of catalyzing material,thus heating the mixture to the temperature necessary for ultimatecombination. passing the mixture through a portion of the catalyzingmaterial, circulating by difference ot density a part of the mixturewhich descends into a cooler region, thus lowering the temperature ofthe mixture to the neighborhood of atmospheric temperature, separatingthe ammonia thus liquefied, heating by indirect contact with thedescending gas the lascending gas separated from ammonia, sending itthen with a part of the mixture which has not participated in thecirculation through another portion of the catalyzing material Where thereaction continues. causing a number of successive separations of theammonia as before and discharging the residual gas.

3. ln an apparatus for the direct synthesis of ammonia, the combinationof a chamber supporting a body of catalyzing material, means permittingpassage of a gaseous mixture in heat interchanging relation with saidcatalyzing material to bring said mixture to the reaction temperatureand means including a cooled receptacle and a connection between saidreceptacle and chamber, said means permitting circulation by gravity ofa part of said mixture, after reaction induced by said catalyzing miasterial, into said receptacle to separate the ammonia and back to saidchamber.

4. In an apparatus for the direct synthesis of ammonia, the combinationof a chamber supporting a body of catalyzing and'means including a-plurality of cooled receptacles and connections between saidreceptacles and chamber, said means permitting successive` 'circulation'by gravity of parts of said mixture, after reaction induced by saidcatalyzing material, into said receptacles to separate ammonia and backto said chamber. y

5. ln an apparatus for the direct synthesis of ammonia, the combinationof an outer shell, an inner shell spaced from the outer shell to provide'a passage, a -body of `catalyzing material in said inner shell throughwhich a gaseous mixture passes, after traveling in said passage 1n heat1n-v terchanging relation with said catalyzing material and meansincluding a cooled receptacle and a connection between said receptacleand thev interior of said outer shell, said means permitting circulationby gravity of part of said gaseous mixture, after reaction induced. bysaid catalyzing material, into said receptacle to separate am.-

` monia and back to said chamber.

6. In an apparatus for the direct synthesis of ammonia, the combinationof an outer `shell, an inner shell spaced from the outer shell toprovide a passage, 'a body of catalyzing material in said inner shellthrough which a gaseous mixture passes after traveling in said passagein heat intercllanging relation With said catalyzing material and meansincluding a cooled receptacle and concentrically arranged tubesconnecting said receptacle with the interior of said outer shell, saidmeans permitting circulation by gravity of part of said gas-A eousmixture, after reaction induced by said catalyzing material, into saidreceptacle to separate ammonia and back to said chamber.

7. In an apparatus for the direct synthesis of ammonia, the combinationof an outer shell, an inner shell spaced from the outer shellvto providea passage, a body of catalyzing material in said inner shell throughwhich a gaseous mixture passes after traveling in said passage in heatinterchanging relation With said catalyzing material and means includinga plurality of cooled receptacles and concentrically arranged tubesconnecting each ofsad receptacles with the interior of said. outershell, said means permitting successive circulation by gravity of partsof said gaseous mixture, after reaction induced by said catalyzingmaterial, into said receptacles to separate ammonia and back to saidlchamber.

'GEORGES CLAUDE.

